<< Forget using a channel. Torsion will kill you on a curved stair. >>
Then I wonder why so many monumental curved stairs have been successfully
designed and fabricated with channel stringers? Maybe it is like the plight
of the poor bumblebee. According to analysis by the best areonautical
engineers the bumblebee cannot possibly fly. You see he has far too much
body weight in proportion to his meager wing area. The bumblebee is unaware
of this hypothesis and flies anyway.
Nothing succeeds like success !!